ROME, Oct 19 (Reuters) - Prime Minister Paolo Gentiloni will make guaranteeing the independence of the Bank of Italy the main criteria in designating a governor, a source in his office said on Thursday.

On Tuesday, the ruling Democratic Party criticised bank governor Ignazio Visco, prompting a rare rebuke from President Sergio Mattarella, who appoints a central banker after evaluating the prime minister’s suggestion.

Visco’s mandate expires at the end of the month but he is eligible to serve another six-year term.

The prime minister makes a recommendation to the president after seeking the opinion of the bank’s supervisory board. (Reporting by Steve Scherer; editign by Philip Pullella)